Determination of the Toxicities of 16 Halogenated Benzenes to Photobacterium Phosphoreum and 2D- and 3D-QSAR Studies

In this paper we take photobacterium phosphoreum （T3） as the experimental bacteria, and determine the half-inhibitory concentration （-1gEC50） against the photobacterium phosphoreum of 16 halogenated benzenes. Using B3LYP method of DFT in the Gaussian 03 program, we obtain the structural and thermodynamic descriptors of 16 halogenated benzenes by fully-optimized calculation at the 6-311G＊＊ level. Taking the structural and thermodynamic descriptors as theoretical descriptors, the 2D QSAR model （R2 = 0.983） was established, which can be utilized to predict -lgEC50 of halogenated benzene according to the corrected linear solvation energy theory based on the experimental data of-lgECs0. In addition, the relationship between the toxicity and 3D spatial structure of the compound is studied by comparing the molecular similarity index analysis （CoMSIA） of 3D-QSAR method. By cross validation, the correlation coefficient q2 of CoMSIA model is 0.687, and the conventional correlation coefficient R2 = 0.958. The model is stable and reliable with great predictive ability. The 3D-QSAR model shows that the toxicity of halogenated benzene compound is mainly affected by the characteristics of hydrophobie field of the substituted halogens.

TOXICITY OF CHLORINATED BENZENES TO MARINE ALGAE

Growth of Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp, Platymonas subcordiformis and Phaeodactylum tricornutum exposed to monochlorobezene (MCB), 1, 2-dichlorobenzene (1, 2-DCB), 1, 2, 3, 4-tetrachlorobenzene (1, 2, 3, 4-TeCB) and pentachlorobenzene (PeCB) was tested. Tests of 72 h-EC50 values showed that the toxicity ranged in the order: MCB<1,2-DCB<1,2,3,4-TeCB<PeCB,and that toxjcity of chlorinated benzene (CB) alone to marine algae was almost in the order: Pyramidomonas sp.< Platymonas subcordiformis<Nannochloropsis oculata < Chlorella marine< Phaeodactylum tricomutum. Study of the QSAR (Quantitative Structure-Activity Relationship) between Kow and toxicity of CBs to marine algae showed good relationships between-logEC50 and logKow.

QSTR Study on the Freshwater Photobacteria Toxicity of Substituted Benzenes

Using a novel freshwater photobacteria — Q67 as an indication organism and the VeritasTM luminometer with 96-well microplate as the testing equipment to determine luminous intensity of photobacteria,the familiar 29 substituted benzenes of the median inhibition toxicities（pEC50）were determined,respectively.The quantum chemical parameters of 29 substituted benzenes in the ideal gas state at 298.15 K and 1.013×105 Pa have been calculated at the B3LYP/6-31G＊ level using Gaussian 03 program.The Quantitative linear relationship（N1）between the pEC50 and two descriptors of 29 substituted benzenes was developed using the variable selection and modeling based on prediction（VSMP）.Model N1 showed good estimation ability and stability（r = 0.8777,q = 0.8482）,which exhibited the difference between empirical and predicted values of 2,3-dimethylphenol was greater（0.5）,so it was given up.Using VSMP to select the optimal descriptors,a 2-variable multiple linear regression model（called model N2）was developed for the pEC50 of substituted benzenes.The r and q for model N2 based on 28 substituted benzenes are 0.8991 and 0.8735,respectively.In order to validate the model,28 substituted benzenes were divided into a training set consisting of 20 compounds and a test set with 8 compounds.The result showed that some main structural factors influencing the pEC50 of substituted benzenes are the lowest unoccupied orbital（ELUMO）and total energy（EHF）.

MICELLIZATION STUDIES OF DODECYL BENZENESULFONIC ACID AND ITS INTERACTION WITH POLYVINYLPYRROLIDONE

Dodecyl benzenesulfonic acid(DBSA)surfactant was used in the present study to find the effect of concentrationon its electrical conductance in solution from 293-323 K above and below the critical micelle concentration(CMC).Themicellization parameters i.e.degree of counter ion binding(β),aggregation number(n)and number of counter ion micelle(m)were measured.The interaction of DBSA with polyvinylpyrrolidone(PVP)was also studied at 293 K throughconductance and surface tension measure ments.A number of important parameters i.e.critical aggregation concentration(CAC),Gibb's free energy(△G)and binding ratio(R)were determined and the effect of NaCl on the CAC and polymersaturation point(PSP)was also investigated.

A Topological Approach to the Correlation of Standard Formation Enthalpy with Path Index of Benzenes Derivatives

A mathematical model formulated as ΔfHθm(g)=a+sum from i=1 to 5bipi(i≠2) was constructed for the relationshipbetween standard formation enthalpy ΔfHθm(g) and path index Pi of substituted benzenes derivatives. An empiric equation for the calculation of ΔfHθm(g) was worked out. The calculated values of standard formation enthalpy based on this model are excellently consistent with those from experimental for 55 organic compounds. The model is shown to be simple and of practical usefulness, particularly when required experimental data are unavailable.

Calculations of Hyperpolarizabilities for Para-disubstituted Benzeneswith the QSPR

A quantitative structure-property relationship (QSPR) was made for the prediction of the hyperpolarizabilities(β) ofpara-disubstituted benzenes with the nonlinear optical properties, and the βca12 calculated by this model accorded better with the experimental values (βexpt) compared with theβcall calculated at the CPHF/6-31G*//HF/STO-3G level of theory, especially whenβ was big.

Ligand Exchange Reaction of Ferrocene with Substituted Benzenes

Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. The product yields of the reactions with alkanoyl- and alkoxybenzenes were low because of the coordination of aluminum chloride to the oxygens of the benzene substituents. Comparing the reactions using o- and p-dimethoxybenzene, the former was revealed to be less reactive;this is likely due to the deviation of the π-electrons of its benzene ring being larger.

A Study on the Inclusion of α-Cyclodextrin with Mono-and 1,4-Disubstituted Benzenes by Neural Networks

The association constant (Ka) values were calculated by the function-strengthen ing neural networks (FNN) for the inclusion complexation of α-CD with mono- and 1,4-disubstituted benzenes. The lnKa predicted by FNN from Rm, π and σ constants of substituents are in great agreement with the experimental data.

Reactions of [60]Fullerene with Di(azidomethyl) benzenes

A diazafulleroid derivative with adjacent 5-6 junctions has been synthesized by the regioselective addition of 1,2-di(azidomethyl) benzene to [60]fullerene. Reaction of [60]fullerene with 1,4-di(azidomethyl) benzene in refluxing chlorobenzene gave a copolymer.

A Model Describing the Time Course and Variability in Toxicity of Hydrophobic Chemicals to Aquatic Organisms-Toxicity of chlorinated benzenes to marine algae

The growth of Chlorella marine, Nannochloris oculate, Pyramimonaos sp., Platymonas subcordiformis and Phaeodactylum tricornutum exposed to chlorobenzene, 1,2-dichlorobenzene, 1,2,3,4-tetrachlorobenzene and pentach-lorobenzene was tested. The Boltzman equation was used to describe organism growth. The time course for uptake of hydrophobic organic chemicals (HOCs) by aquatic organisms was expressed by incorporating growth and, if desired, the effect of metabolism into the HOC bioconcentration process. The probability of any given concentration of HOCs in the organisms causing a specified toxic endpoint was expressed with a modified Weibull distribution function. The combined bioconcentration and probability equations were tested with data for time course of incubation of algae exposed to chlorinated benzenes (CBs). A set of parameters, including the uptake rate constant k 1, the elimination rate constant k 2 and thereafter the bioconcentration factor on a dry weight basis, BCF D, the critical HOC concentration in the organism resulting in a specified toxic endpoint, C* A, and the spread factor, S, could be obtained by fitting only experimental data for percent growth inhibition(%)-time-CB exposure concentration. The average coefficients of variation within CBs were 15.2% for BCF D, 21.0% for k 1, 18.3% for k 2, 8.1% for C* A and 9.7% for S. The variability in toxicity (such as EC 10, EC 50, EC 90) derived from the model equations agreed well with those experimentally observed.

Enabling tandem oxidation of benzene to benzenediol over integrated neighboring V-Cu oxides in mesoporous silica

The direct tandem oxidation synthesis of benzenediol from benzene could simplify or even avoid the separation and purification of reaction intermediates, which is promising but challenged because of the further required immediate consecutive activation of intermediate phenol. In this work, a synergistic benzene tandem-oxidation catalyst that V-Cu bimetallic oxides modified nanoporous silica(VCu-NS)was constructed via a facile assembly strategy which involves addictive negative anion citric acid mediating the intercalation of metal-citric acid chelate in mesopore of silica and subsequent thermal calcination inducing dual-metal active site formation. Such a tactic could make amorphous VOxspecies well covered on the surface of mesopore, and ultrafine copper oxide particles surrounded and neighbored by highly dispersed VOxwith strong interplay in mesopore, which was comprehensively confirmed by various characterizations. Benefiting from the unique V-Cu neighboring effect, the desorption of formed phenol over the catalytic site might be restricted therefore easily further activated by the formed reactive oxidative species, 3VCu-NS shows synergetic tandem-oxidation catalytic activities for benzene towards benzenediol with a selectivity of 57%. The result allows optimal 3VCu-NS to be a promising catalyst for benzenediol synthesis from benzene.

Understanding the interfacial behaviors of benzene alkylation with butene using chloroaluminate ionic liquid catalyst: A molecular dynamics simulation

To better understand the benzene alkylation with chloroaluminate ionic liquids(ILs) as catalyst, the interfacial properties between the benzene/butene binary reactants and chloroaluminate ILs with varying cation alkyl chain length and different anions were investigated using molecular dynamics(MD) simulations. The results indicate that ILs can obviously improve the interfacial width, solubility and diffusion of reactants compared to H_(2)SO_(4). The longer alkyl chains of cations present a density enrichment at the interface and protrude into the binary reactants phase. Furthermore, the ILs consisting of 1-octyl-3-methylimidazolium cations([Omim]^(+)) and the stronger acidity heptachlorodialuminate anions([Al_(2)Cl_(7)]^(-)) are more beneficial to promote the interfacial width and facilitate the dissolution and diffusion of benzene in both the IL bulk and the interfacial region in comparison to the ones with shorter alkyl chains cations and weaker acidity anions. The information gives us a better guideline for the design of ILs for benzene alkylation.

钒基催化剂催化苯羟基化制苯酚反应机理

苯羟基化制苯酚是C—H键向C—O键转化及富有挑战性的课题之一。该文论述了钒基催化剂催化苯羟基化制苯酚反应机理的研究进展。以钒活性中心为主线,着重从自由基、非自由基和双催化活性机理进行了详细介绍,同时分析了双催化活性中心催化剂高效催化的本质和重要性。提出此类催化体系及催化机理能够解决苯环上C—H键难活化和苯酚的深度氧化等问题,是经济与安全并存的苯酚合成方法,依托已有的催化反应机理,开发更稳定且高性能的催化剂,以促进烃类有机化合物资源利用的原始创新。

纳米TiO_(2)微球的制备及光催化降解气相苯特性

以四氯化钛和尿素为原料,通过溶剂热法制备了纳米TiO_(2)微球。利用XRD、FE-SEM、TEM、UV-Vis、BET测试手段对样品的组成、结构、形貌、光学性能、比表面特性进行分析,以气相苯为目标降解物,研究不同溶剂热时间所制备的微球对光催化活性的影响。结果表明,随溶剂热时间的延长,TiO_(2)微球结构经历了实心-核壳-空心的演变过程,但均由20 nm以下的颗粒组成。此类微球的光吸收带边出现明显“蓝移”现象,且光吸收性能较P25 TiO_(2)要高,比表面积是其3~5倍。其中溶剂热时间为6 h所制备的核壳结构微球光催化活性最佳,降解气相苯的矿化率高达93%,高于P25 TiO_(2)近3倍,分析表明,该优异性能得益于核壳结构对光的充分反射吸收和高比表面积导致的吸附协同光催化特性。

顶空-气相色谱法与顶空-气质联用法测定饮用水中苯系物的方法建立及比较

目的:建立顶空-气相色谱法及顶空-气质联用法测定饮用水中常用7种苯系物(苯、甲苯、乙苯、间二甲苯、对二甲苯、邻二甲苯和苯乙烯),探讨两种测定方法的一致性。方法:优化了顶空、色谱、质谱等测定条件,对两种方法的检出限、精密度、准确度进行比较。结果:两种方法的回收率均在90.4%~100.2%,相对标准偏差均在1.1%~4.3%,顶空-气相色谱法的最低检出浓度分别为0.03~0.08μg·L^(-1),顶空-气质联用法的最低检出浓度分别为0.002~0.005μg·L^(-1),测定结果无显著性差异。结论:两种方法操作简单、快速,准确度和灵敏度高,均适用于饮用水中苯系物的日常检测。顶空-气质联用法的灵敏性更高,适用于痕量、基质复杂样品的测定;顶空-气相色谱法适用于高浓度样品的测定。

重整生成油管式反应器液相加氢工艺(FITS)的工业应用

针对某石化公司1.0 Mt/a连续催化重整装置苯产品白土预处理工艺精制深度不够、重组分产量大、白土失活快以及二甲苯加氢系统工艺流程较复杂、能耗大等问题,采用中国石化长岭分公司和湖南长岭石化科技开发有限公司共同开发的重整生成油管式反应器液相加氢工艺(简称FITS工艺)对重整生成油进行脱烯烃处理。该工艺利用氢气纳米级微孔分散技术,使氢气在油相中均匀分散,能有效脱除重整生成油中的烯烃,满足苯产品溴指数小于20 mgBr/(100 g)、混合二甲苯产品溴指数小于50 mgBr/(100 g)的控制要求。FITS工艺的成功投用,可以停用精制苯的白土罐、二甲苯的加氢单元,大幅降低了芳烃处理单元的能耗和运行成本。

气相色谱-质谱法测定酒店空气中7种苯系物

试验运用气相色谱-质谱法测定扩建装修酒店空气中7种苯系物,采用活性炭管采样和二硫化碳解吸,同时对质谱参数和色谱柱进行优化。结果表明,色谱柱能有效分离苯系物中7种待测组分,实现各组分峰完全分离。苯系物具有良好线性关系,相关系数R^(2)>0.999,检出限介于0.60~2.20μg/L,加标回收率为93.9%~98.2%,相对标准偏差为1.8%~4.0%,准确度和精密度良好。苯系物质量控制样品测定表明,该方法符合质控范围。气相色谱-质谱法可用于检测酒店空气中7种苯系物,方法准确可靠,灵敏度高。

光催化苯羟基化制备苯酚反应的研究进展

苯酚是一种重要的有机中间体,在材料、农药、有机合成和药物领域应用广泛。工业上,采用多步异丙苯法制备苯酚,能源消耗高,环境污染严重且苯酚的选择性较低。近年来,随着光催化氧化技术的复苏,光催化苯羟基化制备苯酚迅速成为有机合成领域的研究热点。本文聚焦苯羟基化制备苯酚的光催化剂,综述了近年来在不同氧化剂条件下,光催化苯羟基化制备苯酚反应的研究进展,并对部分反应机理进行了讨论。

原料组成对固体酸催化剂异构化性能的影响

采用等体积浸渍法制备了PSZA(Pt/SO_(4)^(2-)/ZrO_(2)-Al_(2)O_(3))固体超强酸催化剂,在微型固定床反应器上评价了其催化轻烃异构化性能,考察了含不同杂质的n-C_(5)(正戊烷)、n-C_(6)(正己烷)原料在PSZA上的异构化性能。实验结果显示:n-C_(5)与n-C_(6)混合原料的比例基本不影响其各自转化率,与单一组分的转化率相当。原料中异构烷烃i-C_(5)(异戊烷)和i-C_(6)(异己烷)比例越多时,n-C_(5)和n-C_(6)转化率越低,产物组成接近n-C_(5)和n-C_(6)单独转化。甲基环戊烷、苯等杂质会降低PSZA催化n-C_(5)和n-C_(6)的异构化活性,提高反应温度至180℃可以增加PSZA的异构化活性;n-C_(7)(正庚烷)在PSZA上全部裂解,对PSZA催化n-C_(5)和n-C_(6)活性无显著影响。

氨三乙酸配位辅助原位合成Ni@B-HZSM-5对苯和甲醇烷基化反应的影响

利用氨三乙酸离子(NTA3-)与Ni2+的配位作用在强碱溶液中原位合成了负载B-Ni的HZSM-5分子筛(Ni@B-HZSM-5)。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线荧光光谱(XRF)、低温N_(2)吸附-脱附、吡啶红外光谱(Py-IR)、NH3程序升温脱附(NH3-TPD)和H_(2)程序升温还原(H_(2)-TPR)等手段对Ni@B-HZSM-5催化剂进行了表征,采用固定床反应器评价其苯和甲醇烷基化反应性能,并与浸渍法负载的Ni/HZSM-5分子筛催化剂进行了对比。结果表明:原位合成的Ni@B-HZSM-5催化剂中B和Ni分布均匀,具有丰富的弱酸和适宜的加氢能力,甲醇加氢形成甲烷的副反应在一定程度上被抑制;在温度460℃、H_(2)压力0.4 MPa、n(苯)∶n(甲醇)=1.2∶1和质量空速2 h^(-1)条件下,4%Ni@B2-HZSM-5催化苯和甲醇烷基化反应,苯转化率可达46.4%,甲苯和二甲苯总选择性达到95.9%,其中C8芳烃选择性为35.1%,C8芳烃中乙苯摩尔分数为6.1%;并表现出优异的稳定性,比浸渍法Ni/HZSM-5分子筛催化剂性能更佳。